Caithness has emerged as a stronghold for the water vole, according to the results of a survey.
The water vole are the largest British vole
Conservationists believe the mammal is flourishing because there are not the same number of predators as in other parts of the country.
The water vole has been identified by Scottish Natural Heritage as a species in need of priority action.
The survey results will be explained at an event called Biodiversity on the Edge in Thurso on 20 September.
Marina Swanson, Highland Council's Caithness East wildlife ranger, said the study of the vole population was carried out last summer.
She said: "As a result of the water vole survey, the local biodiversity group have discovered that Caithness is one of the few strongholds for this little creature.
"Coverage is very high due to a mix of reasons. One is that there is not a high population of mink, if any, in Caithness."
American mink, a non-native species, prey on water voles and are blamed for declining numbers in other areas.
Cairngorms National Park has an officer dedicated to protecting the animal.
Biodiversity on the Edge has been organised by Caithness Biodiversity Group and will be held at the Environmental Research Institute (ERI) in Thurso from 1700 BST.
There will be short presentations on completed projects such as the water vole survey and habitat enhancement schemes.
The event will be hosted by the ERI and sponsored by the United Kingdom Atomic Energy Authority, which is decommissioning Dounreay in Caithness.